Ethnic and racial minority young men who have sex with men (MYMSM) remain a critical population at the nexus of substance use and HIV/AIDS: a 132% increase in new infections concentrated among African American and Hispanic YMSM has been observed since 2002. The Young Men's Health Project (YMHP), a 4- session intervention utilizing motivational interviewing designed for HIV-negative or untested YMSM ages 18- 29 was found to be efficacious in significantly reducing substance use and condomless anal sex (CAS). To date, this is the first and only RCT of any published trial or CDC DEBI with YMSM to show significant reductions in both substance use and sexual risk. The CDC recently rated YMHP as Best Evidence and placed it on the compendium of Evidence Based Interventions and Best Practices for HIV Prevention. YMHP was tested through an efficacy trial in a research center environment with numerous inclusion and exclusion criteria, and thus, a community-based replication is the crucial next step in studying the intervention's effectiveness in the real world when delivered by staff to their clients. We will conduct a comparative effectiveness trial (CET) with two intensities of treatment offered following field-based HIV counseling and testing (C&T) - the YMHP intervention and enhanced treatment as usual (eTAU) HIV prevention services - in two real-world community based organizations (CBOs) to test their relative effectiveness in reducing substance use and CAS among HIV-negative MYMSM. The Specific Aims are to: 1) adapt the YMHP intervention for delivery in CBOs by peer counselors; 2) test the effectiveness of the YMHP intervention when delivered by peer counselors at two CBOs situated in high HIV incidence neighborhoods in New York City; and 3) assess the cost-effectiveness of YMHP relative to TAU. The proposed study will be implemented over two phases. In Phase 1 we will conduct qualitative research with staff at our collaborating agencies to adapt the efficacious YMHP intervention to the unique needs of MYMSM and incorporate existing systems and approaches utilized by site collaborators to facilitate for delivery by peer counselors. In Phase 2 we will randomize 260 HIV-negative substance using MYMSM into the YMHP intervention or eTAU. Assessments will include behavioral self-report measures, urine testing for substance use, and HIV and STI testing for sexual health outcomes. Working together with our CBO collaborators will help to address practical problems at the frontline of service provision to pave the way for a comprehensive program to reduce substance use and HIV infection among MYMSM. If effective, our program has the potential to exert a sustained and powerful influence on the effectiveness of behavioral interventions for economically disadvantaged, substance using MYMSM who are most at risk for HIV infection.